Sex chromosome replacement is frequent in many vertebrate clades, including fish, frogs, and lizards. In order to understand the mechanisms responsible for sex chromosome turnover and the early stages of sex chromosome divergence, it is necessary to study lineages with recently evolved sex chromosomes. Here we examine sex chromosome evolution in a group of African cichlid fishes (tribe Tropheini) which began to diverge from one another less than 4 MYA. We have evidence for a previously unknown sex chromosome system, and preliminary indications of several additional systems not previously reported in this group. We find a high frequency of sex chromosome turnover and estimate a minimum of 14 turnovers in this tribe. We date the origin of the most common sex determining system in this tribe (XY-LG5/19) near the base of one of two major sub-clades of this tribe, about 3.4 MY ago. Finally, we observe variation in the size of one sex-determining region that suggests independent evolution of evolutionary strata in species with a shared sex-determination system. Our results illuminate the rapid rate of sex chromosome turnover in the tribe Tropheini and set the stage for further studies of the dynamics of sex chromosome evolution in this group.
- MeSH
- cichlidy * genetika MeSH
- fylogeneze MeSH
- jezera MeSH
- mitochondriální DNA genetika MeSH
- molekulární evoluce MeSH
- pohlavní chromozomy genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Tanzanie MeSH
BACKGROUND: In Africa, no cerebral aneurysm treatment guidelines exist. Epidemiology, management, and outcomes after aneurysmal subarachnoid hemorrhage (aSAH) remain poorly understood, with many underdiagnosed cases. Muhimbili Orthopaedic and Neurosurgery Institute (MOI) is the only neurosurgical referral center in Tanzania. The aim of this study is to describe the current aSAH management with regional outcomes and limitations. METHODS: Patients with aSAH confirmed by computed tomography/magnetic resonance angiography between February 2019 and June 2021 were retrospectively studied. The analyzed parameters included demographics, clinical/radiologic characteristics, injury characteristics, and the modified Rankin Scale (mRS) score. RESULTS: In total, 22 patients, with a female/male ratio of 1.4 and a median age of 54 years (interquartile range [IQR], 47.2-63 years) harboring 24 aneurysms were analyzed. Thirteen patients (59.1%) paid out of pocket. The median distance traveled by patients was 537 km (IQR, 34.7-635 km). The median time between admission and treatment was 12 days (IQR, 3.2-39 days). The most common symptoms were headache (n = 20; 90.9%) and high blood pressure (n = 10; 45.4%). Nine patients (40.9%) had Fisher grade 1 and 12 (54.5%) World Federation of Neurosurgical Societies grade I. The most common aneurysms were of the middle cerebral artery (7/29.2%). Fourteen patients (63.6%) underwent clipping; of those, only 4 (28.6%) were operated on within 72 hours. Mortality was 62.5% in the nonsurgical group. Among clipped patients, 78.6% showed favorable outcomes, with no mortality. Endovascular treatment is not available in Tanzania. CONCLUSIONS: To our best knowledge, this is the first study highlighting aSAH management in Tanzania, with its assets and shortcomings. Our data show pertinent differences among international treatment guidelines, with the resultant outcomes, such as high preoperative mortality resulting from delayed/postponed treatment. Regional difficult circumstances notwithstanding, our long-term goal is to significantly improve the overall management of aSAH in Tanzania.
- MeSH
- intrakraniální aneurysma * chirurgie MeSH
- lidé středního věku MeSH
- lidé MeSH
- neurochirurgie * MeSH
- ortopedie * MeSH
- retrospektivní studie MeSH
- subarachnoidální krvácení * diagnostické zobrazování chirurgie MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Tanzanie MeSH
- Klíčová slova
- projekt APOPO, Cricetomys ansorgei,
- MeSH
- chov zvířat organizace a řízení MeSH
- hlodavci MeSH
- kontrola škůdců metody MeSH
- lidé MeSH
- služební zvířata * MeSH
- výzkumný projekt MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Geografické názvy
- Tanzanie MeSH
S rozvolněním protiepidemických opatření, která lze očekávat v jarních a letních měsících, a předpokládaným opětovným nárůstem cestování považujeme za přínosné shrnout aktuální informace o současné situaci výskytu cholery ve světě. Cholera je endemická v řadě zemí světa, zejména v Asii a Africe. V souvislosti s pandemií covid-19 a zhoršující se socioekonomickou situací se její výskyt v některých oblastech významně zvýšil. V zemích Evropské Unie a Evropského hospodářského prostoru se vyskytují jen ojedinělé případy onemocnění cholerou, jedná se především o importy ze zemí s výskytem cholery.
With the relaxation of anti-epidemic measures expected in the spring and summer months and the anticipated resurgence of travel, we find it useful to summarize the current situation of cholera. Cholera is endemic in many countries of the world, particularly in Asia and Africa. In the context of the COVID-19 pandemic and the worsening socioeconomic situation, its incidence has increased significantly in some areas. Only sporadic cases of cholera have been reported in the European Union and European Economic Area countries, which are mainly imports from endemic countries.
- MeSH
- cholera * dějiny epidemiologie přenos MeSH
- cholerové vakcíny terapeutické užití MeSH
- gastroenteritida mikrobiologie MeSH
- hlášení nemocí MeSH
- hodnocení rizik MeSH
- kontrola infekčních nemocí MeSH
- lidé MeSH
- přenos infekční nemoci MeSH
- Check Tag
- lidé MeSH
- Geografické názvy
- Afghánistán MeSH
- Bangladéš MeSH
- Benin MeSH
- Haiti MeSH
- Indie MeSH
- Jemen MeSH
- Kamerun MeSH
- Keňa MeSH
- Mali MeSH
- Mosambik MeSH
- Nepál MeSH
- Niger MeSH
- Nigérie MeSH
- Tanzanie MeSH
BACKGROUND: Blastocystis is a human gut symbiont of yet undefined clinical significance. In a set of faecal samples collected from asymptomatic children of six distant populations, we first assessed the community profiles of protist 18S rDNA and then characterized Blastocystis subtypes and tested Blastocystis association with the faecal bacteriome community. METHODS: Stool samples were collected from 244 children and young persons (mean age 11.3 years, interquartile range 8.1-13.7) of six countries (Azerbaijan 51 subjects, Czechia 52, Jordan 40, Nigeria 27, Sudan 59 and Tanzania 15). The subjects showed no symptoms of infection. Amplicon profiling of the 18S rDNA was used for verification that Blastocystis was the most frequent protist, whereas specific real-time PCR showed its prevalence and quantity, and massive parallel amplicon sequencing defined the Blastocystis subtypes. The relation between Blastocystis and the stool bacteriome community was characterized using 16S rDNA profiling. RESULTS: Blastocystis was detected by specific PCR in 36% (88/244) stool samples and was the most often observed faecal protist. Children from Czechia and Jordan had significantly lower prevalence than children from the remaining countries. The most frequent subtype was ST3 (49%, 40/81 sequenced samples), followed by ST1 (36%) and ST2 (25%). Co-infection with two different subtypes was noted in 12% samples. The faecal bacteriome had higher richness in Blastocystis-positive samples, and Blastocystis was associated with significantly different community composition regardless of the country (p < 0.001 in constrained redundancy analysis). Several taxa differed with Blastocystis positivity or quantity: two genera of Ruminococcaceae were more abundant, while Bifidobacterium, Veillonella, Lactobacillus and several other genera were undrerrepresented. CONCLUSIONS: Asymptomatic children frequently carry Blastocystis, and co-infection with multiple distinct subtypes is not exceptional. Prevalence and quantity of the organism clearly differ among populations. Blastocystis is linked to both faecal bacteriome diversity and its composition.
- MeSH
- asymptomatické infekce epidemiologie MeSH
- Blastocystis klasifikace genetika izolace a purifikace MeSH
- blastocystóza epidemiologie parazitologie MeSH
- dítě MeSH
- feces parazitologie MeSH
- genetická variace MeSH
- lidé MeSH
- mladiství MeSH
- prevalence MeSH
- protozoální DNA genetika MeSH
- ribozomální DNA genetika MeSH
- střevní mikroflóra genetika MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Ázerbájdžán MeSH
- Československo MeSH
- Jordánsko MeSH
- Nigérie MeSH
- Súdán MeSH
- Tanzanie MeSH
A key aim in wildlife disease ecology is to understand how host and parasite characteristics influence parasite transmission and persistence. Variation in host population density can have strong impacts on transmission and outbreaks, and theory predicts particular transmission-density patterns depending on how parasites are transmitted between individuals. Here, we present the results of a study on the dynamics of Morogoro arenavirus in a population of multimammate mice (Mastomys natalensis). This widespread African rodent, which is also the reservoir host of Lassa arenavirus in West Africa, is known for its strong seasonal density fluctuations driven by food availability. We investigated to what degree virus transmission changes with host population density and how the virus might be able to persist during periods of low host density. A seven-year capture-mark-recapture study was conducted in Tanzania where rodents were trapped monthly and screened for the presence of antibodies against Morogoro virus. Observed seasonal seroprevalence patterns were compared with those generated by mathematical transmission models to test different hypotheses regarding the degree of density dependence and the role of chronically infected individuals. We observed that Morogoro virus seroprevalence correlates positively with host density with a lag of 1-4 months. Model results suggest that the observed seasonal seroprevalence dynamics can be best explained by a combination of vertical and horizontal transmission and that a small number of animals need to be infected chronically to ensure viral persistence. Transmission dynamics and viral persistence were best explained by the existence of both acutely and chronically infected individuals and by seasonally changing transmission rates. Due to the presence of chronically infected rodents, rodent control is unlikely to be a feasible approach for eliminating arenaviruses such as Lassa virus from Mastomys populations.
- MeSH
- Arenavirus imunologie MeSH
- hustota populace MeSH
- infekce viry z čeledi Arenaviridae epidemiologie MeSH
- myši MeSH
- nemoci hlodavců epidemiologie MeSH
- protilátky virové MeSH
- séroepidemiologické studie MeSH
- zdroje nemoci veterinární MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Tanzanie MeSH
In light of the current biodiversity crisis, investigating the human impact on non-human primate gut biology is important to understanding the ecological significance of gut community dynamics across changing habitats and its role in conservation. Using traditional coproscopic parasitological techniques, we compared the gastrointestinal protozoan and metazoan symbiont richness of two primates: the Udzungwa red colobus (Procolobus gordonorum) and the yellow baboon (Papio cynocephalus). These species live sympatrically in both protected and unprotected forests within the Udzungwa Mountains of Tanzania with distinct ecological adaptations and diets. Our results showed that terrestrial and omnivorous yellow baboons had 2 (95% CI 1.47-2.73) and 3.78 (2.62-5.46) times higher gut symbiont richness (both including and excluding rare protozoans) compared to the arboreal and leaf-eating Udzungwa red colobus in unprotected and protected forest, respectively. We also found a consistent depletion of symbiont richness in red colobus living in the unprotected forest fragment compared to the continuous protected forests [the latter having 1.97 times (95% CI 1.33-2.92) higher richness], but not in yellow baboons. Richness reduction was particularly evident in the Udzungwa red colobus monkeys, confirming the pattern we reported previously for gut bacterial communities. This study demonstrates the impact of human activities even on the microbiodiversity of the intestinal tract of this species. Against the background of rapid global change and habitat degradation, and given the health benefits of intact gut communities, the decrease in natural gut symbionts reported here is worrying. Further study of these communities should form an essential part of the conservation framework.
- MeSH
- Amoebida * MeSH
- biodiverzita MeSH
- cizopasní červi * MeSH
- Colobus * MeSH
- dieta MeSH
- druhová specificita MeSH
- ekosystém MeSH
- feces MeSH
- lesy MeSH
- lidské činnosti MeSH
- Papio * MeSH
- střeva * MeSH
- symbióza * MeSH
- Trichostomatida * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Tanzanie MeSH
BACKGROUND: Lake Tanganyika is considered a biodiversity hotspot with exceptional species richness and level of endemism. Given the global importance of the lake in the field of evolutionary biology, the understudied status of its parasite fauna is surprising with a single digenean species reported to date. Although the most famous group within the lake's fish fauna are cichlids, the pelagic zone is occupied mainly by endemic species of clupeids (Actinopterygii: Clupeidae) and lates perches (Actinopterygii: Latidae, Lates Cuvier), which are an important commercial source for local fisheries. In this study, we focused on the lake's four lates perches and targeted their thus far unexplored endoparasitic digenean fauna. METHODS: A total of 85 lates perches from four localities in Lake Tanganyika were examined. Cryptogonimid digeneans were studied by means of morphological and molecular characterisation. Partial sequences of the nuclear 28S rRNA gene and the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were sequenced for a representative subset of the specimens recovered. Phylogenetic analyses were conducted at the family level under Bayesian inference. RESULTS: Our integrative approach revealed the presence of six species within the family Cryptogonimidae Ward, 1917. Three out of the four species of Lates were found to be infected with at least one cryptogonimid species. Two out of the three reported genera are new to science. Low interspecific but high intraspecific phenotypic and genetic diversity was found among Neocladocystis spp. Phylogenetic inference based on partial 28S rDNA sequences revealed a sister group relationship for two of the newly erected genera and their close relatedness to the widely distributed genus Acanthostomum Looss, 1899. CONCLUSIONS: The present study provides the first comprehensive characterisation of the digenean diversity in a fish family from Lake Tanganyika which will serve as a baseline for future explorations of the lake's digenean fauna. Our study highlights the importance of employing an integrative approach for revealing the diversity in this unique host-parasite system.
- MeSH
- Bayesova věta MeSH
- biodiverzita MeSH
- biologická evoluce MeSH
- cichlidy parazitologie MeSH
- druhová specificita MeSH
- fylogeneze MeSH
- infekce červy třídy Trematoda epidemiologie parazitologie veterinární MeSH
- jezera parazitologie MeSH
- mitochondriální DNA genetika MeSH
- respirační komplex IV genetika MeSH
- ribozomální DNA MeSH
- RNA ribozomální 28S genetika MeSH
- sekvenční analýza DNA MeSH
- sekvenční seřazení MeSH
- Trematoda anatomie a histologie klasifikace genetika izolace a purifikace MeSH
- žábry parazitologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Tanzanie MeSH
The social-ecological system of the Lake Manyara basin (Northern Tanzania), a UNESCO Biosphere reserve (BR) suffers from social-economic and environmental problems due to decreasing water levels, erosion and land and water use conflicts. We propose an integrated assessment of the social-ecological interactions of the area to support future sustainable management. Within the Drivers-Pressures-State-Impact-Response (DPSIR) framework an integrated literature review and several methods of knowledge collection were combined to identify future management priorities and challenges. During focus groups with farmers and pastoralists, stakeholders confirmed the role played by land use changes as driver and pressure in the landscape, e.g. through increased erosion rates and siltation of the lake. Moreover, economic and social issues were identified as prominent factors being influenced by, or influencing these processes. These statements match the scientific literature. During participatory mapping exercises different spatial and resource allocation perceptions appeared amongst pastoralists and farmers. The multidisciplinary approach proved to be useful to acquire an integrated and comprehensive understanding of the state, challenges and opportunities of Lake Manyara BR, to feed into a decision support system in service of an integrated management plan. Our assessment suggests that improved water governance in a multi-actor approach (with a focus on distribution of benefits, rights, and a specific role of the water authorities) should be a priority for future integrated management strategies. Also, awareness raising amongst decision makers, scientists and local communities is needed to demonstrate the advantages of an integrated approach. And finally, visible and fair mechanisms to share conservation revenues should be designed in a way that local benefits can be obtained together with incentive mechanisms for co-management and conservation.
BACKGROUND: African annual killifishes (Nothobranchius spp.) are adapted to seasonally desiccating habitats (ephemeral pools), surviving dry periods as dormant eggs. Given their peculiar life history, geographic aspects of their diversity uniquely combine patterns typical for freshwater taxa (river basin structure and elevation gradient) and terrestrial animals (rivers acting as major dispersal barriers). However, our current knowledge on fine-scale inter-specific and intra-specific genetic diversity of African annual fish is limited to a single, particularly dry region of their distribution (subtropical Mozambique). Using a widespread annual killifish from coastal Tanzania and Kenya, we tested whether the same pattern of genetic divergence pertains to a wet equatorial region in the centre of Nothobranchius distribution. RESULTS: In populations of Nothobranchius melanospilus species group across its range, we genotyped a part of mitochondrial cytochrome oxidase subunit 1 (COI) gene (83 individuals from 22 populations) and 10 nuclear microsatellite markers (251 individuals from 16 populations). We found five lineages with a clear phylogeographic structure but frequent secondary contact. Mitochondrial lineages were largely congruent with main population genetic clusters identified on microsatellite markers. In the upper Wami basin, populations are isolated as a putative Nothobranchius prognathus, but include also a population from a periphery of the middle Ruvu basin. Other four lineages (including putative Nothobranchius kwalensis) coexisted in secondary contact zones, but possessed clear spatial pattern. Main river channels did not form apparent barriers to dispersal. The most widespread lineage had strong signal of recent population expansion. CONCLUSIONS: We conclude that dispersal of a Nothobranchius species from a wet part of the genus distribution (tropical lowland) is not constrained by main river channels and closely related lineages frequently coexist in secondary contact zones. We also demonstrate contemporary connection between the Ruvu and Rufiji river basins. Our data do not provide genetic support for existence of recently described cryptic species from N. melanospilus complex, but cannot resolve this issue.
- MeSH
- Cyprinodontidae genetika MeSH
- ekosystém * MeSH
- fylogeneze MeSH
- fylogeografie MeSH
- genetická variace * MeSH
- genetický drift MeSH
- mikrosatelitní repetice MeSH
- mitochondriální DNA genetika MeSH
- populační genetika MeSH
- řeky MeSH
- respirační komplex IV genetika MeSH
- sladká voda MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Tanzanie MeSH
